Technical I want to “pour” a hammer form, how ? What?

By Jove, I think that's what I was struggling to recall! Don't know anything about it though.

Chris

 

Like Steve, I think concrete could be a cheap and strong option. Wipe a bond preventer on, a couple layers of fiberglass to make a smooth surface, then after that cures, fill it with a few inches of concrete and rebar. Plan ahead for flipping the thing over without bending the original panel.

 

Upgrade to ballistic concrete?

Chris

 

One issue with concrete is it takes literally years of curing to reach full strength, which is why I suggest exploring the more exotic mixes. And I think you'd want a pretty substantial form, I'd pour something 6+ inches thick. You will definitely want some steel in there, some rebar, maybe even some mesh.

 

Kirksite is what the big boys use.

Here is another thread from a couple years back

https://www.jalopyjournal.com/forum/threads/pourable-die-material.1241776/

 

According to Bob Mortimer, that would be Fuji 9...

 

Check this out. Pretty impressive...

https://machinalabs.ai/

Cheers!

 

Would it be possible to make and reinforce a female form to hydroform basic blanks. Then make a buck with reinforced edges to use as a hammer form to fold edges and add details.

 

Use the original to make a sand mould then get a steel foundry to cast the impression

 

Everyday C4 mix, which is what most streets and driveways are, will reach 4,000 PSI strength in about a week under most summertime conditions. I doubt anyone will be hand hammering over 4,000 pounds a square inch. And if you make it six inches thick you will need a forklift or skid loader to move it.

 

C4 ? Blow shit up with that ???

I kind of went down the concrete thought trail.
ive seen plenty concrete chip, spall, scratch and dent from dumb stuff and a little heat is not good. Parking curbs get beat up.

Epoxy grout for setting machines is pretty damn durable though and easy. Maybe I’ll try some of that

 

Trust me, there is a big difference between concrete cured for weeks versus some that's cured for years. I've drilled enough holes in it to know (35+ years in commercial/industrial construction). And slab strength is related to how well its 'bedded'. A 2" thick, relatively new slab on a workbench will crack pretty easily from impact. Reinforcing steel will mitigate that to a degree, at least preventing separation.

 

I think its Kirksite or something like that

 

You could build a wooden buck within a 1/4" of the panel and then pour it with red 1060. We use this all the time in pattern making. It's kind of a hard rubberish 2 part "epoxy" that'd very durable. Ud need some release wax and ud have to build a form around the part to keep the 1060 from running out. Not sure if it would work for a hammer form tho.

 

I wonder if a poured die could be used in the hydroforming process? I suspect you wouldn't get full detail but could hand-finish that. No idea of cost, but where you live there has to be somebody doing it.

 

I tried a concrete form once to make a conversion panel to put early headlights in a later jaguar nose. it didn't last long.

 

What kind of concrete did you use?

I Was talking with a friend this evening, he’s thinking high strength grout, 13,400 psi after 4 days. This what they would put under a Drop forge or huge stamping press

• Critical equipment baseplates, soleplates & columns
• Crane rails, ball mills, crushers
• On-shore wind turbines requiring high torsional and dynamic loads
• Rolling, stamping, drawing and finishing mills for the steel and aluminium industries.

 

That is taking the load on a flat surface, not being used as a mold.

 

Cass Nawrocki, a fantastic metalworker, often used concrete to make forms to hammer over.

 

1 piece or 100 pieces?

 

That’s true, won’t cost me anything but time to try something notebook sized

 

Was going to suggest this as well. If 3D scanning and CNC machining is cost prohibitive, the same type of epoxies and urethanes are also available as pourable resins: https://industry.sika.com/en/home/a...asting-resinsfortooling/sikabiresin-g519.html

 

I'd have to find his book and look, but I know he used to make repro parts for very rare cars, not real mass production, but probably in the dozens?

 

Isn't concrete going to blow your 1000 lb limit?

 

It would be pretty close +/- 200

 

Is there any way that conventional sheetmetal forming means could be used to basically make the shape, and then the more detailed stuff completed with a different process? Kind of a two stage production.

I thought Kirksite was where William Shatner worked?

 

I don’t know if you’ve ever “flow formed” a piece with an air hammer but it’s very easy, very fast, very smooth, and very nice. Did I mention fast?
On my coupe project I went over doing it for the quarter windows and other pieces. You get quite a bit of time wrapped up in making the forms and just minutes into making metal pieces. Some where in there is a point where it’s a wash on time spent or maybe there’s a point of diminishing returns and it actually takes longer, but on piece number 2 you win if the form can take the beating or it’s just a great win win situation on first piece.

 

Kind of like post 35? Seriously, do people even read through threads before posting?

 

For CNC you'd need to write the code or laser scan your part into code. Do it old school without a computer- make yourself a 3D router pantograph to carve it out of a block of particle board. There are some videos on YouTube but you'll need to make longer arms for the size you need.

 

There is probably a good reason the old world Italian and English coachbuilders did bodies the old fashioned way one at a time.